Conventionally, there have been known various types of room temperature-curable organopolysiloxane compositions capable of being cured into elastomer (silicone rubber) shaped products at room temperature (25° C.±10° C.) through a cross-linking reaction due to a condensation reaction, when coming into contact with water in the air. Among these compositions, those of dealcoholization-type are cured by releasing alcohols through a condensation reaction at the time of cross-linking; and are preferably used as sealing, adhesive and coating materials for electric and electronic devices or the like, since they characteristically do not produce unpleasant odors, nor do they corrode metals.
Typical examples of a composition of the above type include a composition comprised of a hydroxyl-endblocked polyorganosiloxane, alkoxysilane and an organic titanium compound; a composition comprised of an alkoxysilyl-endblocked polyorganosiloxane, alkoxysilane and alkoxy titanium; a composition comprised of a linear polyorganosiloxane whose silethylene group-containing alkoxysilyl end is blocked, alkoxysilane and alkoxy titanium; and a composition comprised of a hydroxyl-endblocked or alkoxy-endblocked polyorganosiloxane and an alkoxy-α-silylester compound (Patent documents 1 to 4).
Although these compositions exhibit certain levels of storage stability, water resistance and moisture resistance, a perfectly satisfactory level has not yet been reached. Moreover, an insufficient fast curability has been observed with these compositions.
As mentioned above, an organosiloxane polymer having a reactive (hydrolyzable) alkoxysilyl group(s) at its terminal(s) is conventionally known. This polymer has its polymer end group already blocked by an alkoxysilyl group, thus exhibiting an insignificant change (decrease) in curability with time and a superior storage stability. Further, a workability (e.g. viscosity, thixotropy) of such polymer can be arbitrarily adjusted, and superior properties (e.g. hardness, tensile strength and elongation at break) have also been observed with such polymer as it forms an elastomer through a cross-linking reaction by reaction with water in the air.
However, those of dealcoholization-type have exhibited an insufficient curability due to their low reactivity with water in the air, as compared to curable organopolysiloxane compositions of other known curing types such as those of deoximation type, de-acetic acid type and deacetone type.
The inventors of the present invention have proposed a polymer having an alkoxysilyl-vinylene group (alkoxysilyl-ethenylene group) at its terminal and a composition comprised of such polymer, for the purpose of developing a room temperature-curable organopolysiloxane composition capable of forming a cured product through a superior fast curability, and having a superior moisture resistance (i.e. curability exhibited after stored under a moisture condition) (Patent documents 5 and 6). Although these polymer and composition have excellent properties, there have to be newly synthesized polymers with various molecular weights and substituent structures, thus making it difficult to produce such polymer and composition in an industrially advantageous manner.